1. Field of the Invention
This invention relates to safety equipment for use in a mine and more particularly to a mine life line system.
2. Description of the Prior Art
In mining a seam of coal normally at least three shafts are started into the seam. These spaced apart shafts are continued as coal is extracted from the seam. The spaced apart shafts are interconnected by cross passages at regular intervals. Even if the mining direction changes the three shafts are maintained. The three shafts are utilized for moving men and material into the mine and for removing coal. Air is drawn into the mine and through the interconnected shafts. At least one of the shafts is a return air shaft. Air which is drawn into the mine is returned to the outside through this return air shaft. The return air shaft is normally designated an escape way and is used only by mine personnel. The shafts can extend a great distance into the seam, often several miles, and the shafts can often have several changes of direction. To facilitate the escape of miners in the event of an accident, it is West Virginia Law to have a life line installed in the escape way, which a miner can follow by touch to the outside of the mine. A problem with a simple life line, however, is that when an accident occurs, a miner may become very disoriented and be uncertain of the direction in which to follow the life line.
In some areas of the United States, the use of life lines within a mine is presently required. For example, in West Virginia it is required that two-way communication and life line or its equivalent shall be provided from the fresh air base to all rescue or recovery teams. The Underground Coal Mine Safety Laws for the state of West Virginia presently provides: "On or after the first day of April, one thousand nine hundred seventy-eight, each operator shall provide lifeline cords with reflective material at twenty-five foot intervals, from the last open crosscut to the surface along a designated escapeway ventilated by return air: Provided, that in case of a shaft mine such lifeline cords shall extend from the last open crosscut to the bottom of the designated escape shaft. Such lifeline cord shall be of durable construction sufficient to allow miners to see and to use effectively to guide themselves out of the mine in the event of an emergency."